Cancerous cells are part of your body — they've just mutated such that they don't respond to signals that tell them to die or slow their rate of replication. Th

Cancerous cells are part of your body — they've just mutated such that they don't respond to signals that tell them to die or slow their rate of replication. The reason your immune system doesn't recognize them is because they are literally part of you. This is why specifically targeted cancer cures are so hard: there's almost nothing that distinguishes cancer cells from normal cells.